Replaced all 4 spark plugs and all 4 coil packs now having crazy issues.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Pinged, Apr 4, 2026 at 1:44 AM.

  1. Pinged

    Pinged New Member

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    Car was driving fine and no misfires prior to starting job. 296k miles.
    After replacing coils and plugs with NGK iridium from rockauto and Denso coils from eBay, I made sure all connectors clicked into place and added some marvel mystery oil to engine oil to help clean it up a little. on start up, the car made a loud rattling noise. Turned it off quickly and put the old coil packs and did an oil change Incase any carbon got loose and the rattling went away.
    Went for a test drive and it misfired then the engine turns off and the car started driving off the hybrid battery only.
    Scanned the car and recieved codes for
    -engine won’t start
    -engine not receiving fuel
    I’m thinking of reinstalling the old spark plugs Incase the new ones weren’t gapped properly or got the gap got damaged so the old ones can go along with the old coil packs back how it previously was and see if that will bring it back to normal. Any help or input would be appreciated.
     
    #1 Pinged, Apr 4, 2026 at 1:44 AM
  2. JC91006

    JC91006 Senior Member

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    The coils don't need replacement if they are working fine. And ebay stuff has so many counterfeits, it's probably not worth the gamble.

    In your case now, I would put all the old stuff back and see if things go back to normal. If it does, then visually inspect the new plugs to make sure none of them got damaged. It only takes 1 bad one to cause all your issues.
     
    #2 JC91006, Apr 4, 2026 at 2:16 AM
    Brian1954 and xw20_driver like this.
  3. lexidium

    lexidium Active Member

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    I agree about Ebay, Even the coils saying denso are often fakes.
    It's about £70 for one denso coil so you get what you pay for.
     
    #3 lexidium, Apr 4, 2026 at 9:59 AM
  4. rogerthat

    rogerthat Active Member

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    I bought Denso plugs through the dealership and had considered buying coils on Ebay through a high volume highly rated seller but I then decided to just keep the original coils based on forum feedback. Out of interest, can you post a link to the exact products you purchased on Ebay?
     
    #4 rogerthat, Apr 4, 2026 at 10:39 AM
  5. Pinged

    Pinged New Member

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    Priuschat wont let me post the link because I haven’t met the requirements, the eBay seller name is Injector-Rehab professional tho. Straight out the packaging I had a feeling they were counterfeit based on the looks of the box because a box of Denso coil packs for an Altima looked quite different and it opened differently too. I had thoughts of returning it but I just said to give the a try
     
    #5 Pinged, Apr 4, 2026 at 10:43 AM
  6. BiomedO1

    BiomedO1 Senior Member

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    What are the actual codes?

    Did you compare and verify they were the correct parts BEFORE installing them?
     
    #6 BiomedO1, Apr 4, 2026 at 11:39 AM
    Brian1954 likes this.
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